super1: report truncated device

When the metadata is at the start of the device, it is possible that it
describes a device large than the one it is actually stored on.  When
this happens, report it loudly in --examine.

....
   Unused Space : before=1968 sectors, after=-2047 sectors DEVICE TOO SMALL
          State : clean TRUNCATED DEVICE
....

Also report in --assemble so that the failure which the kernel will
report will be explained.

mdadm: Device /dev/sdb is not large enough for data described in superblock
mdadm: no RAID superblock on /dev/sdb
mdadm: /dev/sdb has no superblock - assembly aborted

Scenario can be demonstrated as follows:

mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md/test started.
mdadm: stopped /dev/md/test
   Unused Space : before=1968 sectors, after=-2047 sectors DEVICE TOO SMALL
          State : clean TRUNCATED DEVICE
   Unused Space : before=1968 sectors, after=-2047 sectors DEVICE TOO SMALL
          State : clean TRUNCATED DEVICE

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

diff --git a/super1.c b/super1.c
index 71af860c0e3ec9d4a5e2ea6ca1c4ad1a4c44c453..58345e68b97c7e32cf935e95f4f0985cc3723318 100644 (file)
--- a/super1.c
+++ b/super1.c
@@ -406,12 +406,18 @@ static void examine_super1(struct supertype *st, char *homehost)
 
        st->ss->getinfo_super(st, &info, NULL);
        if (info.space_after != 1 &&
-           !(__le32_to_cpu(sb->feature_map) & MD_FEATURE_NEW_OFFSET))
-               printf("   Unused Space : before=%llu sectors, after=%llu sectors\n",
-                      info.space_before, info.space_after);
-
-       printf("          State : %s\n",
-              (__le64_to_cpu(sb->resync_offset)+1)? "active":"clean");
+           !(__le32_to_cpu(sb->feature_map) & MD_FEATURE_NEW_OFFSET)) {
+               printf("   Unused Space : before=%llu sectors, ",
+                      info.space_before);
+               if (info.space_after < INT64_MAX)
+                       printf("after=%llu sectors\n", info.space_after);
+               else
+                       printf("after=-%llu sectors DEVICE TOO SMALL\n",
+                              UINT64_MAX - info.space_after);
+       }
+       printf("          State : %s%s\n",
+              (__le64_to_cpu(sb->resync_offset)+1) ? "active":"clean",
+              (info.space_after > INT64_MAX)       ? " TRUNCATED DEVICE" : "");
        printf("    Device UUID : ");
        for (i=0; i<16; i++) {
                if ((i&3)==0 && i != 0)
@@ -2206,6 +2212,7 @@ static int load_super1(struct supertype *st, int fd, char *devname)
                tst.ss = &super1;
                for (tst.minor_version = 0; tst.minor_version <= 2;
                     tst.minor_version++) {
+                       tst.ignore_hw_compat = st->ignore_hw_compat;
                        switch(load_super1(&tst, fd, devname)) {
                        case 0: super = tst.sb;
                                if (bestvers == -1 ||
@@ -2312,7 +2319,6 @@ static int load_super1(struct supertype *st, int fd, char *devname)
                free(super);
                return 2;
        }
-       st->sb = super;
 
        bsb = (struct bitmap_super_s *)(((char*)super)+MAX_SB_SIZE);
 
@@ -2322,6 +2328,21 @@ static int load_super1(struct supertype *st, int fd, char *devname)
        if (st->data_offset == INVALID_SECTORS)
                st->data_offset = __le64_to_cpu(super->data_offset);
 
+       if (st->minor_version >= 1 &&
+           st->ignore_hw_compat == 0 &&
+           (dsize < (__le64_to_cpu(super->data_offset) +
+                     __le64_to_cpu(super->size))
+            ||
+            dsize < (__le64_to_cpu(super->data_offset) +
+                     __le64_to_cpu(super->data_size)))) {
+               if (devname)
+                       pr_err("Device %s is not large enough for data described in superblock\n",
+                              devname);
+               free(super);
+               return 2;
+       }
+       st->sb = super;
+
        /* Now check on the bitmap superblock */
        if ((__le32_to_cpu(super->feature_map)&MD_FEATURE_BITMAP_OFFSET) == 0)
                return 0;